Unit for feeding difficult to feed materials

ABSTRACT

Difficult to feed materials, such as quick-set additives for wet or dry concrete, are fed into contact with the concrete in particular form. A compact mass of the material is advanced into contact with an abrasive means to erode away the material in particulate form from the compacted mass at a predetermined rate. The particulate material is then conveyed in a fluid medium into contact with wet or dry concrete. Dual side-by-side units are provided with means to separately actuate each unit to provide uninterrupted delivery of the particulate material to a use location.

I Oct. 8, 1974 United States Patent [191 Broadfoot 1 1 UNIT FOR FEEDINGDIFFICULT TO FEED MATERIALS Primary Examiner-Roy Lake AssistantExaminer-E. F. Desmond Attorney, Agent, or FirmSeed, Berry, Vernon &Baynham [22] Filed:

[57] ABSTRACT Difficult to feed materials, such as quick-set additives[21] Appl. No.: 300,180

for wet or dry concrete, are fed into contact with the [52] US. 241/15,241/38, 241/101.6, concrete in particular form A compact mass of thematerial is advanced into contact with an abrasive means to erode awaythe material in particulate form from the compacted mass at apredetermined rate.

28 2 88 .8 22 2 N 682 M 2 B11 7 M Z "4 W A M5 "18 "3 1. n 4 m2 Mb. "6 r.m 1 m cm 9 hm.. 1: 8 55 1:1

The particulate material is then conveyed in a fluid References Citedmedium into contact with wet or dry concrete. Dual UNITED STATES PATENTSside-by-side units are provided with means to separately actuate eachunit to provide uninterrupted delivery of the particulate material to ause location.

241/38 X 241/282 241/282 8 Claims, 5 Drawing Figures 2,561,043 3,182,9205/1965 Daniels. 3,688,997 9/1972 U11ner.......

PATENTEU 81374 3,840,186

SHEET 1 0f 3 FIGO 2 PATENHU BET 74 rm //1 fi SHEET 2 BF 3 UNIT FORFEEDING DIFFICULT TO FEED MATERIALS BACKGROUND OF THE INVENTION used areexpensive and difficult to accurately feed because of their tendency tocake, build up on sliding surfaces and adhere to the surfaces of thecontainer holding the same. These additives are also dusty, extremelynoxious and caustic to the extent that use of such additives has beenforbidden by some states due to working condition regulations. Powderedadditives of this type are commercially available and sold under thetradenames Tricosol by Chemische Fabrik Grunau, GmbH, Accelleset" byProtex Industries, Inc., Unicrete X by Sayder Manufacturing Company andQuickset by Master Builders. Tricosol, for exampie, is a blend of sodiumcarbonate and sodium aluminate in a weight ratio of about 2:1. Means aredisclosed for metering a quick-setting additive into contact with wet ordry concrete in US. Pat. application Ser. No. 175,764, filed Aug. 27,1971; however, the metering device disclosed has a feed rate whichvaries plus or minus percent or more. This results in inefficientwasteful use of the additive. In addition, if the additive is allowed tosit in the holding vessel of the metering device described in theapplication for a period of time or allowed to come into contact with adamp atmosphere, it sets to a hard, rock-like mass which is unworkable.It has thus remained a problem to devise means for accurately anduniformly feeding quick-set additives for wet or dry concrete.

SUMMARY OF THE INVENTION This invention relates to a method and means ofaccurately and uniformly feeding a hard to feed material, such as aquick-set additive for concrete as a particulate material wherein thematerial is first formed into a compacted mass and the mass advancedinto contact with an abrading means which erodes away a portion of thematerial as a particulate material for conveyance by suspension in aflow of fluid medium to a use area.

The objects of this invention are to provide: (1) a process andapparatus for accurately and uniformly feeding a hard to feed materialas a particulate material; (2) a process and apparatus for first forminga hard to feed material into a compacted mass and then advancing themass into contact with abrading means which erodes away the material ata predetermined rate as particulate material for feeding by suspensionin a fluid medium location; (3) to provide a process and apparatus foraccurately and uniformly metering quickset additives for wet or dryconcrete in a simplified and uncomplicated manner.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of anoverall system for 2 metering a quick-set additive for concrete inconjunction with a concrete pump;

FIG. 2 is a top view of the feed unit of this invention;

FIG. 3 is a cross-sectional view of the feed unit illustrating mountingof the abrading wheel and material feeding means;

FIG. 4 is a vertical cross-sectional view of the abrading wheel housingand abrading wheel therein along section line 4-4 of FIG. 3; and

FIG. 5 is a schematic of the control system for switching between onefeed unit and another.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The feed unit described is mostuseful in feeding hard to feed materials in particulate form from acompacted mass of material in block or stick form. FIG. 1 illustratesone use of the feed unit 1 in conjunction with a concrete pump 2, thefeed unit feeding the quick-set additive as a finely divided powdersuspended in a fluid medium through conduit 3 intersecting conduit 4through which wet concrete is metered. The feed unit may also be usedfor feeding other difficult to feed materials which, because of theirphysical properties, are difficult to feed accurately and/or at auniform rate. The concrete pump, shown in phantom in FIG. 1, forms nopart of this invention, but is described in US. Pat. No. 3,180,272. Thefeed unit described may also be used in conjunction with a conventionaldry type spraying apparatus, such as Gunite, wherein the quicksetadditive would be introduced into the air fed dry concrete in advance ofthe spray nozzle where water is added to the mixture.

The feed and metering unit comprises a frame 10 on which are mountedhorizontally oriented material guide cylinders 11 and 12 held in spacedrelation by spacer 13. The open ended cylinders 11 and 12 communicate atone end with cylindrical extensions 14 secured around openings in thecylindrical walls 15 of the abrading wheel housing 18, each providedwith a top wall 16 and bottom wall 17. Each abrading wheel 27 is mountedon a shaft 19 journalled for rotation in the housing 15. The shaft 19 isoffset relative to the vertical axis of housing 15. Shaft 19 extends upthrough the top plate 16 of each housing and through suitable bearings20 and seals 21 carried by housing 22 and held in place by retainer ring22a. The splined upper shaft portion 24 of each shaft is connected to ahydraulic motor 25 mounted in housing 26. The abrading member 27 of theabrading wheels may be any material capable of eroding away thecompacted material as a particulate material such as a stacked seriesofspaced apart'wire brushes secured about shaft 19. The diameter of theabrading members is less than the inner diameter of housing 15. Inletand outlet ports 28 and 29 extend through the top and bottom plates 16and 17 of the abrading wheel housings and may be located as illustratedin FIG. 3. The inlet and outlet ports may be directly opposed orlaterally offset. The abrading wheel may be rotated in either directionbut is preferably rotated in a clockwise direction as illustrated byFIG. 3. Inlet conduits 30 are connected between a source of compressedgas (air) and the inlet ports 28. Outlet conduits 31 connected to outletports 29 intersect to form conduit 3 which intersects with the concretestream flowing through conduit 4. Compressed air or other fluid mediumis provided to the inlet port at suitable pressures ranging from to 200psi. An air inlet 61 connected to the air supply entering throughconduit is preferably provided adjacent the hub of the abrading wheelhousing to prevent accumulation and build-up of the powdered additive inthat area.

A compacted mass of material 60 is placed in one of the guide cylinders11. The outer diameter of the compacted material is made slightly lessthan the inner diameter of the guide cylinders for ease of insertion ofthe material. The material is advanced into contact with the abradingwheel by a loosely fitting plunger 32 connected to a hollow push rod 33which extends the length of the guide cylinder and out through anopening in cap 34 secured to the end of the guide opposite the abradingwheel housing by fasteners 34a extending through flanges 35 and 36. Aprojecting shoulder 37 of the cap, having an outerdiameter approximatelythe same as the inner diameter of the guide cylinder, includes arecessed O-ring 38 to seal the guide cylinder against loss of airpressure. Bearings 39 are provided for the push rods 33, these beingheld in a recess of the cap 34 by a retainer ring 40 and snap ring 41.Seals 42 around the push rod prevent loss of gas pressure within theguide cylinder. The end of the push rod extending beyond the cap 34 issecured tothe piston 43 of hydraulic cylinder 44 by linkage 45. As thepiston 43 is retracted, the compacted material in the guide cylinder isadvanced by plunger 32 and push rod 33 into contact with the abradingwheel at a predetermined rate.,The rate of advance may be varied byconnecting the hydraulic cylinders to a variable hydraulic pump (seeFIG. 5). When the piston 43 of the cylinder 44 reaches the end of itsstroke, control means (FIG. 5) are provided to activate the adjacentmounted unit to provide uninterrupted feed of the material to the uselocation. While the adjacent feed unit is working, the cap 34 of theempty guide cylinder is disconnected from linkage 45, cap 34 removed andthe plunger 32 and push rod 33 removed to insert another compacted massof material into the empty guide cylinder. Air inlets 62 through guidecylinders 11 and 12 are connected to the air supply entering throughconduit 30 to prevent accumulation of the powdered additive in the guidecylinders behind the pistons 32. I

Referring to FIG. 5, cam operated spool valves control activation of thedual side-by-side feed units. The control system on the right is shownin activated position while the control system on the left is ininactive position. Shift of cam operated valve 50 to the position showneffects shifting of air operated valve 51 which, in turn, shiftsfour-way air operated valve 51 which, in turn, shifts four-way airoperated valve 52, relay valve 53, and spring-centered, four-way airactuated valve 54 to (l) initiate retraction of the piston 43 ofhydraulic cylinder 44, (2) furnish compressed gas through line 55 andvalve 53 to the cylindrical housing, and (3) start hydraulic motor 25'powering the abrading wheel 18. The rate of retraction of piston 43 iscontrolled by a variable pump 50 to control the feed rate of theparticulate material. When the piston has reached the end of its strokeand the compacted mass of material is about exhausted spool valve 50 isshifted to exhaust position and spool valve 56, controlling activationof the duplicate unit, shifted to the active position. Shift of valve56, in turn, effects shifting of air operated four-way valve 52, relayvalve 57, and spring-centered, four-way 4 air operated valve 58 foroperation of the duplicate unit in the same manner as previouslydisclosed.

Quick-set additives for wet or dry concrete in uncompacted form aregenerally fluffy, hygroscopic materials which, on compaction undersuitable pressures, form a compacted mass of material which isself-binding. The material is compressed into sticks approximately thelength and diameter of the guide and cylinder of the feed unit (about 4inches in diameter and 6 feet in length). It has been determined thattwo six-foot long sticks of the quick-set additive will furnishsufficient additive for operating a concrete pump of the typeillustrated in FIG. 1 for about 1 hour. The pressure needed to compactthe material into stick form varies depending on the particular materialused. If necessary, a binder, which does not affect the end use of theproduct, may be added to material.

I claim:

1. In a system for applying a stream of wet, semi-fluid material settingto a hard end-product within seconds after ejection from a nozzle onto awork surface, the system including a pump metering and pumping apredetermined amount of the semi-fluid material to a discharge nozzle,and metering unit for metering and delivering a dry, particulate,quick-set additive for the semi-fluid material into contact with thestream of semi-fluid material in a predetermined weight ratio ofadditive to semi-fluid material, the improvement comprising providing ametering and feeding unit converting a compacted mass of the quick-setadditive to a particularized state and feeding the same into contactwith the stream of semi-fluid material suspended in a flow ofpressurized gas, the unit comprising:

a housing having inlet and outlet ports therein,

a source of pressurized gas connected to the inlet port,

conduit means connecting the stream of semi-fluid material, abrasivemeans mounted for rotation within the houspower means for rotating theabrasive means,

means continuously advancing a compacted mass of the quick-set additiveinto contact with the rotating abrasive means to particularize thecompacted additive,

the pressurized gas entering the housing through the inlet portentraining the particularized additive therein and conducting theadditive suspended in the flow of pressurized gas out of the housinginto contact with the stream of semi-fluid material through the conduitmeans.

2. The system of claim 1 wherein the abrasive means includes an abradingwheel mounted on a shaft, the wheel having a diameter less than theinternal diameter of the housing and mounted for rotation within thehousing with its axis laterally offset from the axis of the housing.

3. The system of claim 1 wherein the means advancing the compacted massis adapted to move at a uniform, controlled rate.

4. The system of claim 2 wherein the means for advancing the compactedmass includes (1) a cylindrical guide chamber holding the compactedadditive communicating at one end with the housing and disposed so thatits axis intersects the axis of the housing perpendicularly, (2) closuremeans at the opposite end of the guide chamber providing access to thechamber and outlet port with the sealing the chamber from thesurrounding atmosphere,

and (3) fluid power means including a plunger extending through theclosure means and contacting the compacted mass within the guide chamberso as to advance the mass into contact with the rotating abrading wheelat a predetermined rate to convert the compacted mass to particularizedform.

5. A system for spraying a continuous stream of wet, semi-fluid materialsetting to a hard end-product within seconds after ejection from anozzle for application on a surface, the system including a pump formetering and pumping predetermined amounts of the semi-fluid material tothe nozzle and a metering unit for metering and delivering a dry,particulate, quick-set additive for the semi-fluid material into contactwith the stream of semi-fluid material prior to discharge from thenozzle, the improvement comprising a metering unit converting acompacted mass of the quick-set additive to particularized form fordelivery suspended in a flow of pressurized gas into contact with thestream of semifluid material, the unit comprising:

a cylindrical housing having inlet and outlet ports therein,

a source of pressurized gas connected to the inlet port,

an abrading wheel mounted on a shaft journalled for rotation about anaxis laterally offset from the axis of the housing,

power means for rotating the abrading wheel,

a cylinder holding a compacted mass of the quick-set additivecommunicating with the housing and disposed so that its axis intersectsthe axis of the cylindrical housing perpendicularly,

closure means at the opposite end of the cylinder providing access tothe cylinder and sealing the cylinder from the surrounding atmosphere,

fluid power means including a plunger extending through the closuremeans and contacting the compacted mass of quick-set additive within thecylinder for advancing the compacted mass of the quick-set additive intocontact with the rotating abrading wheel at a predetermined rate toconvert the compacted mass to particularized form,

the pressurized gas entering through the inlet port entraining theparticularized additive in the gas stream and conveying it suspended inthe flow of pressurized gas into contact with the stream of semi-fluidmaterial.

6. The system of claim 5 wherein the abrading wheel is a cylindricalwire brush.

7. Duplicate units in side-by-side relation for converting a mass ofcompacted quick-set additive for wet or dry concrete to a particulatestate and feeding the same suspended in a flow of pressurized gas intocontact with the concrete, comprising:

a material guide chamber holding the compacted additive,

a housing mounted ajdacent the chamber having an opening thereincommunicating with the interior of the chamber for advance of thecompacted additive thereinto,

an abrading wheel mounted in the housing for eroding away the portion ofthe compacted additive contacting the outer circumferential surfacethereof as a finely divided material,

power means operating the abrading wheel,

inlet and outlet ports through the housing adjacent the area of contactof the compacted additive and abrading wheel,

means providing a pressurized gas to the inlet port for delivery of thepowdered additive eroded from the compacted mass through the outlet portin admixture with the pressurized gas,. variable rate feed means toadvance the compacted additive into contact with the abrading wheel, and

control means fordeactivating one unit and simultaneously activating theadjacent unit for continuous,

uninterrupted feed of the additive.

8. A method of applying quick-setting concrete to a work surface,comprising:

pumping a stream of wet, semi-fluid concrete to a discharge area fordischarge from a nozzle onto the work surface,

metering a predetermined amount of a particulate quick-set additive forthe concrete suspended in a flow of pressurized gas into contact withthe stream of semi-fluid material prior to discharge thereof onto thework surface by (a) abrading a compacted mass of the quick-set additiveto convert a portion thereof to particularized form at a predeterminedrate, and (b) feeding the particularized additive suspended in a flow ofpressurized gas into the stream of semi-fluid concrete.

1. In a system for applying a stream of wet, semi-fluid material settingto a hard end-product within seconds after ejection from a nozzle onto awork surface, the system including a pump metering and pumping apredetermined amount of the semi-fluid material to a discharge nozzle,and metering unit for metering and delivering a dry, particulate,quick-set additive for the semi-fluid material into contact with thestream of semi-fluid material in a predetermined weight ratio ofadditive to semifluid material, the improvement comprising providing ametering and feeding unit converting a compacted mass of the quick-setadditive to a particularized state and feeding the same into contactwith the stream of semi-fluid material suspended in a flow ofpressurized gas, the unit comprising: a housing having inlet and outletports therein, a source of pressurized gas connected to the inlet port,conduit means connecting the outlet port with the stream of semi-fluidmaterial, abrasive means mounted for rotation within the housing, powermeans for rotating the abrasive means, means continuously advancing acompacted mass of the quick-set additive into contact with the rotatingabrasive means to particularize the compacted additive, the pressurizedgas entering the housing through the inlet port entraining theparticularized additive therein and conducting the additive suspended inthe flow of pressurized gas out of the housing into contact with thestream of semi-fluid material through the conduit means.
 2. The systemof claim 1 wherein the abrasive means includes an abrading wheel mountedon a shaft, the wheel having a diameter less than the internal diameterof the housing and mounted for rotation within the housing with its axislaterally offset from the axis of the housing.
 3. The system of claim 1wherein the means advancing the compacted mass is adapted to move at auniform, controlled rate.
 4. The system of claim 2 wherein the means foradvancing the compacted mass includes (1) a cylindrical guide chamberholding the compacted additive communicating at one end with the housingand disposed so that its axis intersects the axis of the housingperpendicularly, (2) closure means at the opposite end of the guidechamber providing access to the chamber and sealing the chamber from thesurrounding atmosphere, and (3) fluid power means including a plungerextending through the closure means and contacting the compacted masswithin the guide chamber so as to advance the mass into contact with therotating abrading wheel at a predetermined rate to convert the compactedmass to particularized form.
 5. A system for spraying a continuousstream of wet, semi-fluid material setting to a hard end-product withinseconds after ejection from a nozzle for application on a surface, thesystem including a pump for metering and pumping predetermined amountsof the semi-fluid material to the nozzle and a metering unit formetering and delivering a dry, particulate, quick-set additive for thesemi-fluid material into contact with the stream of semi-fluid materialprior to discharge from the nozzle, the improvement comprising ametering unit converting a compacted mass of the quick-set additive toparticularized form for delivery suspended in a flow of pressurized gasinto contact with the stream of semi-fluid material, the unitcomprising: a cylindrical housing having inlet and outlet ports therein,a source of pressurized gas connected to the inlet port, an abradingwheel mounted on a shaft journalled for rotation about an axis laterallyoffset from the axis of the housing, power means for rotating theabrading wheel, a cylinder holding a compacted mass of the quick-setadditive communicating with the housing and disposed so that its axisintersects the axis of the cylIndrical housing perpendicularly, closuremeans at the opposite end of the cylinder providing access to thecylinder and sealing the cylinder from the surrounding atmosphere, fluidpower means including a plunger extending through the closure means andcontacting the compacted mass of quick-set additive within the cylinderfor advancing the compacted mass of the quick-set additive into contactwith the rotating abrading wheel at a predetermined rate to convert thecompacted mass to particularized form, the pressurized gas enteringthrough the inlet port entraining the particularized additive in the gasstream and conveying it suspended in the flow of pressurized gas intocontact with the stream of semi-fluid material.
 6. The system of claim 5wherein the abrading wheel is a cylindrical wire brush.
 7. Duplicateunits in side-by-side relation for converting a mass of compactedquick-set additive for wet or dry concrete to a particulate state andfeeding the same suspended in a flow of pressurized gas into contactwith the concrete, comprising: a material guide chamber holding thecompacted additive, a housing mounted ajdacent the chamber having anopening therein communicating with the interior of the chamber foradvance of the compacted additive thereinto, an abrading wheel mountedin the housing for eroding away the portion of the compacted additivecontacting the outer circumferential surface thereof as a finely dividedmaterial, power means operating the abrading wheel, inlet and outletports through the housing adjacent the area of contact of the compactedadditive and abrading wheel, means providing a pressurized gas to theinlet port for delivery of the powdered additive eroded from thecompacted mass through the outlet port in admixture with the pressurizedgas, variable rate feed means to advance the compacted additive intocontact with the abrading wheel, and control means for deactivating oneunit and simultaneously activating the adjacent unit for continuous,uninterrupted feed of the additive.
 8. A method of applyingquick-setting concrete to a work surface, comprising: pumping a streamof wet, semi-fluid concrete to a discharge area for discharge from anozzle onto the work surface, metering a predetermined amount of aparticulate quick-set additive for the concrete suspended in a flow ofpressurized gas into contact with the stream of semi-fluid materialprior to discharge thereof onto the work surface by (a) abrading acompacted mass of the quick-set additive to convert a portion thereof toparticularized form at a predetermined rate, and (b) feeding theparticularized additive suspended in a flow of pressurized gas into thestream of semi-fluid concrete.